Many offices and the like in recent years are configured as systems in which terminals such as personal computers are connected via a network to image processing devices such as digital multifunctional machines. It is typical for these kinds of image processing devices to be configured as multifunctional machines that serve such roles as a printer, a scanner, and a copying machine. In functioning as a printer, such a multifunctional machine receives print data (image data or text data) via the network from a terminal and, based on the print data, records the images and text onto recording paper. Or, when functioning as a scanner, it displays an image of a scanned original on the display of a terminal. Moreover, when functioning as a copying machine, it records onto recording paper the image of the original that was scanned with the scanning function.
Image processing devices such as these greatly contribute to improved work efficiency in offices. However, as they can be used simply and easily, they are sometimes subjected to unauthorized usage for private (personal) purposes other than work.
Conventional technology that focuses on inhibiting such unauthorized usage of image processing devices is disclosed in Japanese Laid-Open Patent Publication No. Hei 11-24859 (hereafter “patent document 1”) and Japanese Laid-Open Patent Publication No. 2002-116901 (hereafter “patent document 2”).
A configuration is disclosed in patent document 1 in which a plurality of personal cards are provided on which individual information corresponding to users of a system is recorded, and a key counter with a plurality of insertion slots for the personal cards is connected to a multifunction printer. One of the insertion slots is for the copying function of the printer, and another insertion slot is for the printing function of the printer, and when a personal card is read at the insertion slot of the key counter for the printing function, the individual information that is read out is verified against the individual information at the time of logging on to the network. The result of this verification is that the print data saved by a server can be printed by a printer on the condition that the individual information is in agreement. Furthermore, the number of sheets printed by each user can be recorded in a data storage portion when a print operation is carried out.
The invention in patent document 2 has been proposed by the inventor of the present invention. When data is to be recorded onto recording paper, the ID code of the user who requested the data to be recorded is stored in association with the recorded data, thus enabling an administrator to know which users have recorded which data, and making it possible to ascertain unauthorized usage of an image processing device. Furthermore, in patent document 2, whether or not to store data in which the ID code of the user is associated with the recorded image data is determined based on preset storage ratios for each user.
However, with the techniques disclosed in the above-described patent documents, it is possible that a large volume of image data that does not need to be recorded, that is, even information that does not involve unauthorized usage, is nonetheless recorded. And for this reason, not only is a storage device with a large storage capacity required, but numerous tasks become required to carry out the job of monitoring with an administrator distinguishing whether or not unauthorized usage has been made of recorded information, thus increasing the burden on the administrator.
It should be noted that consideration is given in patent document 2 to presetting storage ratios on a per-user basis and recording information that has a high probability for unauthorized usage, but the effectiveness therein was as yet insufficient and further improvements were required.